The word used in the commentary was "monotonous" (the meaning
being "one-track" rather than "boring"). Some of the suggestions
seemed close, but the differences may perhaps repay further
thought. "Slack" (nurui) means ceding the initiative, which
is certainly not the fault of the move played as Black has to
answer. "Slow" seems passable, but is not quite there.

I think it was a 7-kyu (Mike Vaughn) that gave the best answer
because he got the right spot for the suggested improvement: d10
(more aggressive strategically than d9). The point about this
move is that its is duo-tone - it has a dual purpose: chasing
as well as staking out a side. The game's 42 (f11) really just
chased.

The commentary pointed out that White 42 at f14 was an
irrelevance: Black f13, White f15, and now Black can play the
big move c14 because he doesn't have to worry about being cut
through with White g14 (he can live at the top with the comb
formation).